采用相干量子输运理论和传递矩阵方法，数值计算了两端具有铁磁接触的双势垒异质结构(F/DB/F)中自旋相关的隧穿几率和自旋极化率。结果表明，隧穿几率和自旋极化率随阱宽的增加发生振荡周期不随垒厚变化的周期性振荡；Rashba自旋轨道耦合强度的增加加大了隧穿几率和自旋极化率的振荡频率；隧穿几率和自旋极化率的振幅和峰谷比强烈依赖于两铁磁电极中磁化方向的夹角。与铁磁/半导体/铁磁（F/S/F）磁性隧道结中的结果相比，发现垒厚的增加增大了隧穿几率和自旋极化率的峰谷比，自旋极化率的取值明显增大，并具有自旋劈裂和自旋翻转现象出现。

Using the coherent quantum transport theory and transfer matrix method, we investigate the spin-dependent transmission coefficient and spin polarization of electrons tunneling through double barriers (DB) sandwiched between two ferromagnets (F). The results indicate that the transmission coefficient and spin polarization oscillate periodically with the increasing of the well width, and the period of oscillation is independent of the barriers thickness. The oscillation frequencies of the transmission coefficient and spin polarization increase with the increasing of the Rashba spin-orbit coupling strength. The amplitude and peak-to-valley ratio of the transmission coefficient and spin polarization are strongly dependent on the relative orientation of the two magnetizations in the left and right ferromagnets. In additional, compared to the ferromagnet/semiconductor/ferromagnet (F/S/F) magnetic tunneling junction, the peak-to-valley ratio of the transmission coefficient and spin polarization increase with the increasing of the barrier thickness, the large spin polarization value can be obtained, and the spin splitting and spin-flipping properties can be observed.